Sensor array, apparatus for dispensing a vapor phase reactant to a reaction chamber and related methods

ABSTRACT

An apparatus for dispensing a vapor phase reactant to a reaction chamber is disclosed. The apparatus may include: a vessel having an inner volume configured to contain a liquid chemical; an array of sensors configured for detecting a fill level of the liquid chemical disposed within the inner volume, wherein the array of sensors are vertically distributed within the inner volume with an irregular vertical interval between adjacent sensors. The apparatus may also include: an inlet disposed in the vessel and configured for providing a carrier gas into the inner volume; and an outlet disposed in the vessel and configured for dispensing the vapor phase reactant from the inner volume to the reaction chamber. A sensor array for detecting the fill level of a liquid chemical is also disclosed, as well as methods for dispensing a vapor phase reactant to a reaction chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and claims priority to U.S. patentapplication Ser. No. 16/108,950 filed Aug. 22, 2018 titled SENSOR ARRAY,APPARATUS FOR DISPENSING A VAPOR PHASE REACTANT TO A REACTION CHAMBERAND RELATED METHODS, the disclosure of which is hereby incorporated byreference in its entirety.

FIELD OF INVENTION

The present disclosure relates generally to sensor arrays and anapparatus for dispensing a vapor phase reactant to a reaction chamberand in particular to an apparatus including a vessel for containing aliquid chemical, which includes an array of sensors configured fordetecting the fill level of the liquid chemical. The disclosure alsoincludes methods for dispensing a vapor phase reactant to a reactionchamber.

BACKGROUND OF THE DISCLOSURE

Semiconductor processing apparatus commonly use one or more vapor phasereactants, i.e., precursors, as source chemicals for performingsemiconductor substrate processes, such as, for example, deposition,cleaning, and etching processes. The vapor phase reactants may becontained in a source vessel in a liquid state and are subsequentlyconverted to a vapor state for transport to a reaction chamberassociated with a semiconductor processing apparatus.

High volume semiconductor fabrication facilities may utilize a largevolume of liquid chemicals resulting in the requirement to eitherregularly re-charge the vessel with additional precursor, oralternatively, frequently exchange the discharged vessel for fullvessels.

However, there are some forms of liquid chemical precursor which are notreadily adaptable for re-charge of the vessel. For example, a particularliquid chemical may be easily degraded or a particular liquid chemicalmay become strongly attached to the inner surface of the vessel duringthe re-charge procedure. In addition, the exchange of the dischargedvessel for a full vessel may incur undesirable down time for thesemiconductor processing apparatus and may also necessitate the need forsafe storage of a large number of chemical vessels. Therefore, there isa desire to limit the frequency of chemical vessel exchanges or chemicalvessel re-charges.

One fundamental method for reducing the frequency of chemical vesselexchange or chemical vessel re-charge is to increase the size of thevessel thereby allowing the vessel to store more liquid chemicalprecursor. For example, deposition processes, such as, for example,atomic layer deposition processes, may utilize one or more chemicalvessels as the precursor source(s) for the deposition of materials. Thechemical vessel may be connected to a source of one or more carriergases. The carrier gases may be introduced into the chemical vessel anddrawn over the surface of, or bubbled through, the liquid chemicalcontained within the vessel. The resulting evaporation of the liquidchemical causes a vapor of the liquid chemical to become entrained inthe carrier gas to thereby produce the vapor phase reactant which can bedispensed to a reaction chamber.

It has been found that the maximum evaporation rate of the liquidchemical occurs directly below the carrier gas inlet, i.e., where thecarrier gas flow is most proximate to the liquid chemical. It has alsobeen found that as the liquid chemical is consumed, the fill level ofthe liquid chemical reduces, increasing the distance between the carriergas inlet and the exposed surface of the liquid chemical. The increasein distance between the carrier gas inlet and the exposed surface of theliquid chemical can result in an unwanted variation in the vapor phasereactant flow out from the chemical vessel to the reaction chamber. Forexample, as the liquid chemical within the vessel is consumed and thedistance between the carrier gas inlet and the exposed surface of theliquid chemical increases, the flow of vapor phase reactant from thechemical vessel to the reaction chamber may decrease, resulting in anundesirable variation in semiconductor processing conditions.

Accordingly, apparatus and methods are desirable for monitoring the filllevel of a liquid chemical disposed within a vessel and regulating asemiconductor process in response to the fill level of the liquidchemical within the vessel.

SUMMARY OF THE DISCLOSURE

This summary is provided to introduce a selection of concepts in asimplified form. These concepts are described in further detail in thedetailed description of example embodiments of the disclosure below.This summary is not intended to identify key features or essentialfeatures of the claimed subject matter, nor is it intended to be used tolimit the scope of the claimed subject matter.

In some embodiments of the disclosure, an apparatus for dispensing avapor phase reactant to a reaction chamber is provided. The apparatusmay comprise: a vessel having an inner volume configured to contain aliquid chemical; an array of sensors configured for detecting a filllevel of the liquid chemical disposed within the inner volume, whereinthe array of sensors are vertically distributed within the inner volumewith an irregular vertical interval between adjacent sensors; an inletdisposed in the vessel and configured for providing a carrier gas intothe inner volume; and an outlet disposed in the vessel and configuredfor dispensing the vapor phase reactant from the inner volume to thereaction chamber.

In some embodiments of the disclosure, a sensors array configured fordetecting the fill level of a liquid in a vessel is provided. The sensorarray may comprise: a vertical supports; and an array of sensorsconfigured for detecting a fill level of the liquid disposed within aninner volume of the vessel; wherein the array of sensors comprises aplurality of sensors which are vertically distributed along the verticalsupport with an irregular vertical interval between adjacent sensors.

In some embodiments of the disclosure, a method for dispensing a vaporphase reactant to a reaction chamber is provided. The method maycomprise: flowing a carrier gas into an inlet of a vessel having aninner volume configured to contain a liquid chemical; sensing a filllevel of the liquid chemical by providing an array of sensor configuredfor detecting a fill level of the liquid chemical disposed within theinner volume, wherein the array of sensors are vertically distributedwithin the inner volume with an irregular vertical interval betweenadjacent sensors; and flowing a vapor phase reactant from an outlet ofthe vessel to a reaction chamber.

For purposes of summarizing the invention and the advantages achievedover the prior art, certain objects and advantages of the invention havebeen described herein above. Of course, it is to be understood that notnecessarily all such objects or advantages may be achieved in accordancewith any particular embodiment of the invention. Thus, for example,those skilled in the art will recognize that the invention may beembodied or carried out in a manner that achieves or optimizes oneadvantage or group of advantages as taught or suggested herein withoutnecessarily achieving other objects or advantages as may be taught orsuggested herein.

All of these embodiments are intended to be within the scope of theinvention herein disclosed. These and other embodiments will becomereadily apparent to those skilled in the art from the following detaileddescription of certain embodiments having reference to the attachedfigures, the invention not being limited to any particular embodiment(s)disclosed.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

While the specification concludes with claims particularly pointing outand distinctly claiming what are regarded as embodiments of theinvention, the advantages of embodiments of the disclosure may be morereadily ascertained from the description of certain examples of theembodiments of the disclosure when read in conjunction with theaccompanying drawings, in which:

FIG. 1 is a graph illustrating the non-linear relationship betweenmaterial deposition rate in an exemplary atomic layer deposition processand the percentage of liquid chemical remaining in a vessel;

FIG. 2 is a cross-sectional schematic diagram of a vessel including anarray of sensors according to the embodiments of the disclosure;

FIG. 3 is a cross-sectional schematic diagram of a vessel including anarray of sensors and an additional array of sensors according to theembodiments of the disclosure;

FIG. 4 is a cross-section schematic diagram of a vessel including anarray of sensors according to additional embodiments of the disclosure;and

FIG. 5 is simplified schematic diagram of a semiconductor processingapparatus comprising a vessel including an array of sensors according tothe embodiments of the disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Although certain embodiments and examples are disclosed below, it willbe understood by those in the art that the invention extends beyond thespecifically disclosed embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Thus, it is intended thatthe scope of the invention disclosed should not be limited by theparticular disclosed embodiments described below.

The illustrations presented herein are not meant to be actual views ofany particular material, structure, or device, but are merely idealizedrepresentations that are used to describe embodiments of the disclosure.

As used herein the term “fill level” may refer to the vertical locationof the upper exposed surface of a liquid chemical disposed within avessel.

The embodiments of the disclosure may include apparatus and methods fordispensing a vapor phase reactant to a reaction chamber. In particular,the embodiments of the disclosure may include a vessel configured forcontaining a liquid chemical wherein the vessel includes an array ofsensors within the inner volume of the vessel. The array of sensors maybe configured to detect the fill level of the liquid chemical within theinner volume and generate a control output dependent on the fill levelof the liquid chemical. The fill level dependent control output from thearray of sensors may be provided to a controller associated with asemiconductor processing apparatus. The controller may in turn generatean associated control signal based on the fill level of the liquidchemical which is utilized to ensure a uniform reaction rate within areaction chamber associated with the semiconductor processing apparatus.For example, the control output generated by the controller may beutilized to regulate the temperature of one or more heaters associatedwith the semiconductor processing apparatus wherein the one or moreheaters are configured for controlling the temperature of the liquidchemical within the inner volume. Therefore, as the fill level of theliquid chemical decreases, the temperature of the liquid chemical may bemodified to ensure a uniform dose of vapor phase reactant is provided tothe reaction chamber, thereby allowing a uniform deposition rate ofmaterial being deposited within the reaction chamber.

A problem associated with uniformity of deposition rate and the filllevel of a liquid chemical in an inner volume of a vessel is illustratedin FIG. 1 . FIG. 1 illustrates the relationship between the normalizeddeposition rate of an exemplary atomic layer deposition process and thepercentage of liquid chemical remaining in the vessel. Examination ofFIG. 1 indicates that as the volume of liquid chemical in the vesselreduces, i.e., the fill level drops within the vessel, the normalizeddeposition rate of the exemplary atomic layer deposition process alsodecreases. Further examination of FIG. 1 illustrates that the decreaseobserved in the normalized deposition rate is non-linear as indicated bythe two distinct regimes labelled as the regime 100 and the regime 102.For example, the normalized deposition rate of the regime 100 and thenormalized deposition rate of the regime 102 represent different lineardecreases in the normalized deposition rate with the decrease innormalized deposition rate being greater in the regime 100, where thefill level of the liquid chemical is greater, than in the regime 102,where the fill level of the liquid is lower, i.e., the volume of liquidchemical in the inner vessel is most depleted.

Accordingly, it may be advantageous to more closely monitor and controlthe semiconductor processing apparatus when the fill level of the liquidchemical is greater, as in this regime, i.e., the regime 100, thedeposition rate of material is more dependent on a change in fill levelwithin the inner volume of the vessel. Vice versa when the fill levelwithin the inner volume of the vessel is less, i.e., more volume of theliquid chemical has been discharged, less monitoring and control of thesemiconductor processing apparatus may be needed, as the deposition ratemay be less dependent on the rate of change of the fill level of theliquid chemical within the inner volume of the vessel.

Therefore, the embodiments of the disclosure may include an apparatusfor dispensing a vapor phase reactant to reaction chamber. The apparatusmay comprise: a vessel having an inner volume configured to contain aliquid chemical; an array of sensor configured for detecting a filllevel of the liquid chemical disposed within the inner volume, whereinthe array of sensors are vertically distributed within the inner volumewith an irregular vertical interval between adjacent sensors. Theapparatus may also comprise: an inlet disposed in the vessel andconfigured for providing a carrier gas into the inner volume; and anoutlet disposed in the vessel and configured for dispensing the vaporphase reactant from the inner volume to the reaction chamber.

The embodiments of the disclosure may be understood in more detail withreference to FIG. 2 which illustrates a cross-sectional schematicdiagram of an exemplary chemical delivery apparatus for dispensing avapor phase reactant to a reaction chamber according to the embodimentsof the disclosure.

In more detail, the apparatus 200 comprises a vessel 202 having an innervolume 204 configured to contain a liquid chemical 206. The vessel 202may be fabricated from corrosion resistant materials, such as, forexample, quartz materials, or stainless steel. The vessel 202 may beconfigured to contain a liquid chemical 206 up to a maximum volume ofthe liquid chemical of greater than 2 liters, or greater than 4 liters,or even greater than 6 liters.

The vessel 202 may also comprise an inlet 208 disposed in the vessel 202and configured for providing a carrier gas into the inner volume 204. Insome embodiments, the inlet 208 may provide a carrier gas which entersthe inner volume 204 and contacts the liquid chemical 206 at the exposedliquid surface, i.e., the fill level 210. In alternative embodiments,the inlet 208 may extend into the inner volume 204 and further into theliquid chemical 206, as illustrated by dashed line 208A. In suchembodiments, the carrier gas injected into the inner volume 204 throughthe inlet 208, 208A may be bubbled through the liquid chemical 206 tofurther agitate the liquid chemical 206. The inlet 208 may also comprisea valve 210 utilized to control the flow of the carrier gas into theinner volume 204 of the vessel 202.

The vessel 202 may also comprise an outlet 212 disposed in the vessel202 and configured for dispensing a vapor phase reactant from the innervolume 204 to a reaction chamber (not shown). The outlet 212 may alsocomprise a valve 214 utilized to control the flow of the vapor phasereactant from the inner volume 204 of the vessel 202 to a reactionchamber.

The apparatus 200 may also comprise an array of sensors 216 configuredfor detecting a fill level 210 of the liquid chemical 206 disposedwithin the inner volume 204, wherein the array of sensors 216 arevertically distributed within the inner volume 204 with an irregularvertical interval between adjacent sensors.

In more detail, the array of sensors 216 may comprise a linear array ofsensors including a plurality of individual sensors, such as sensors218A, 218B, 218C, 218D, and 218E. In some embodiments, each of thesensors may comprise a digital sensor which may either detect thepresence of a liquid chemical at the sensor location or alternativelythe absence of a liquid chemical at the sensor location. Therefore, thevertically distributed linear array of sensors 216 may sense the filllevel of the liquid chemical within the inner volume 204 of the vessel206. In some embodiment, each of the sensors may comprise a digitalultrasonic sensor.

In some embodiments, the array of sensors 216 may be housed on avertical support 220 which is disposed in the vessel through vessel port222. Therefore, in some embodiments, a sensor array configured fordetecting the fill level of a liquid within a vessel may comprise: avertical support 220; and an array of sensors 216 configured fordetecting a fill level of the liquid chemical disposed within an innervolume of the vessel, wherein the array of sensors 216 comprises aplurality of sensors (218A, 218B, 218C, 218D, and 218D) which arevertically distributed along the vertical support 220 with an irregularinterval between adjacent sensors. In alternative embodiments, the arrayof sensors may be attached to an internal sidewall of the vessel 202.

In some embodiments of the disclosure, the vertical interval betweenadjacent sensors may be irregular and in particular embodiments thevertical interval between adjacent sensors may increase from anupper-most sensor 218A to a lower-most sensor 218E, in other words thevertical distance between adjacent sensors may increase from the top ofthe vessel down to the bottom of the vessel. Therefore, in someembodiments, the concentration of sensors may be greater in an upperportion of the inner volume 204 compared with the concentration ofsensors in a lower portion of the inner volume 204.

An additional configuration of an apparatus for dispensing a vapor phasereactant to a reaction chamber is illustrated in FIG. 3 . The apparatus300 of FIG. 3 is substantially the same as apparatus 200 of FIG. 2therefore only the additional elements of apparatus 300 are described indetail.

In more detail, FIG. 3 illustrates a cross-sectional schematic diagramof an apparatus 300 for dispensing a vapor phase reactant to a reactionchamber. The apparatus 300 comprises a vessel 302 configured to containa liquid chemical 306 and an array of sensors 216 configured fordetecting the fill level of the liquid chemical 300 disposed within theinner volume 304, wherein the array of sensors 216 are verticallydistributed within the inner volume with an irregular vertical intervalbetween adjacent sensors, as described previously with reference toapparatus 200 of FIG. 2 . The vessel 300 also includes an inlet 208 withan associated valve 210 as described previously in reference toapparatus 200 of FIG. 2 . The vessel also includes an outlet 212 with anassociated valve 214 as also described previously in reference toapparatus 200 of FIG. 2 .

The apparatus 300 of FIG. 3 may also comprise an additional array ofsensors 316 configured for detecting the fill level 310 of the liquidchemical 306 disposed within the inner volume 304, wherein theadditional array of sensors 316 are vertically distributed within theinner volume 304 with an irregular interval between adjacent sensors.

In more detail, the additional array of sensors 316 may comprise alinear array of sensors including a plurality of individual sensors,such as sensors 318A, 318B, and 318C. In some embodiments, each of thesensors of the additional array 316 may comprise a digital sensor whichmay either detect the presence of a liquid chemical at the sensorlocation or alternatively the absence of a liquid chemical at the sensorlocation. Therefore, the vertically distributed linear additional arrayof sensors 316 may sense the fill level of the liquid chemical 306within the inner volume 304 of the vessel 302. In some embodiment, eachof the sensors of the additional array 316 may comprise a digitalultrasonic sensor.

In some embodiments, the additional array of sensors 316 may be housedon a vertical support 320 which is disposed in the vessel 302 throughvessel port 322. In alternative embodiments, the additional array ofsensors 316 may be attached to an internal sidewall of the vessel 302.For example, the array sensors 216 and the additional array of sensors316 may be disposed on opposing sidewalls of the vessel 302.

In some embodiments of the disclosure, the vertical interval betweenadjacent sensors of the additional array 316 may be irregular and inparticular embodiments the vertical interval between adjacent sensors ofthe additional array 316 may increase from an upper-most sensor 318A toa lower-most sensor 318C, in other words the vertical distance betweenadjacent sensors may increase from the top of the vessel down to thebottom of the vessel. Therefore, in some embodiments, the concentrationof sensors may be greater in an upper portion of the inner volume 304compared with the concentration of sensors in a lower portion of theinner volume 304.

In some embodiments of the disclosure, each sensor of the array 216 andthe additional array 316 may be disposed at a different verticalposition within the inner volume 304. For example, as illustrated inFIG. 3 each of the individual sensors of the array 216 (sensors 218A,218B, 218C, 218D, and 218E) and the additional array 316 (sensors 318A,318B, and 318C) are disposed at different vertical positions within theinner volume 304 of the vessel 302. The array of sensors 216 and theadditional array of sensors 316 may be utilized in combination to detectthe fill level 310 of the liquid chemical 306 contained within thevessel 302. The combination of the array 216 and the additional array316 may enhance the sensitivity of detection of the fill level 310 ofthe liquid chemical 306 as well as improving detection reliability. Forexample, when utilizing digital ultrasonic sensors for detecting eitherthe presence or absence of the liquid chemical 306 the sensor signal maybe degraded by a number of factors, including, but not limited to,signal noise, heat, or liquid pollutants. Therefore, utilizing acombination of both the array of sensors 216 and the additional array ofsensors 316 may minimize the degradation in the detection of the filllevel 310 of the liquid chemical 306.

In some embodiments, further linear arrays of sensors may be disposedwithin the vessel 300 for further improving the sensitivity of the filllevel detection and reliability of the detection system. For example,the vessel 302 may include two or more, three or more, or even five ormore linear arrays of sensors configured for detecting the fill level310 within the vessel 302, wherein each individual sensor of the arraysare disposed at different vertical positions within the vessel 302.

An additional configuration of an apparatus for dispensing a vapor phasereactant to a reaction chamber is illustrated in FIG. 4 . The apparatus400 of FIG. 4 is substantially the same as apparatus 200 of FIG. 2therefore only the additional elements of apparatus 400 are described indetail.

In more detail, FIG. 4 illustrates a cross-sectional schematic diagramof an apparatus 400 for dispensing a vapor phase reactant to a reactionchamber. The apparatus 400 comprises a vessel 402 configured to containa liquid chemical 406. The vessel 402 also includes an inlet 208 with anassociated valve 210 as described previously in reference to apparatus200 of FIG. 2 . The vessel also includes an outlet 212 with anassociated valve 214 as also described previously in reference toapparatus 200 of FIG. 2 .

The apparatus 400 may also include an array of sensors configured fordetecting the fill level 410 of the liquid chemical 406 disposed withinthe inner volume 404, wherein the array of sensors are verticallydistributed within the inner volume 404 with an irregular verticalinterval between adjacent sensors.

In more detail, in this non-limiting example embodiment, each sensor ofthe array of sensors comprises a vertical support which may be insertedthrough a vessel port disposed in the lid of the vessel wherein thevertical support is configured for supporting a single sensor at adistinct vertical position within the inner volume 404 of the vessel402. For example, a first vertical support 420A may be inserted througha first vessel port 422A disposed in the lid of the vessel and the firstvertical support 420A may support a first sensor 418A at a firstvertical position within the inner volume 404 of the vessel 402. Asecond vertical support 420B may be inserted through a second vesselport 422B disposed in the lid of the vessel and the second verticalsupport 420B may support a second sensor 418B at a second verticalposition within the inner volume 404. A third vertical support 420C maybe inserted through a third vessel port 422C disposed in the lid of thevessel and the third vertical support 420C may support a third sensor418C at a third vertical position within the inner volume 404. A fourthvertical support 420D may be inserted through a fourth vessel port 422Ddisposed in the lid of the vessel and the fourth vertical support 420Dmay support a fourth sensor 418D at a fourth vertical position withinthe inner volume 404. Any number of vertical supports and theirassociated sensors may be utilized within the inner volume 404 of thevessel 402. For example, the apparatus 400 may include three (3) or morevertical supports and associated sensors, or five (5) or more verticalsupports and associated sensors, or even eight (8) or more verticalsupports and associated sensors.

In some embodiments of the disclosure, the vertical interval, i.e., thevertical distance, between adjacent sensors (418A, 418B, 418C, and 418D)may be irregular and in particular embodiments the concentration ofsensors in the upper region of the inner volume 404 may be greater thanthe concentration of sensors in the lower region of the inner volume404. In some embodiments, each of the sensors (418A, 418B, 418C, and418D) may comprise a digital sensors which may detect either thepresence or absence of the liquid chemical 400 and each of the sensors(418A, 418B, 418C, and 418D) may comprise a digital ultrasonic detector.

The exemplary chemical delivery apparatus and exemplary sensor arrays ofthe current disclosure may be utilized in a number of applications. As anon-limiting example, the exemplary chemical delivery apparatus andsensors arrays of the current disclosure may be utilized as componentsof a precursor delivery system configured for supplying one or moreprecursors to a reaction chamber of a semiconductor processingapparatus.

In more detail, FIG. 5 illustrates an exemplary semiconductor processingapparatus 500 which comprises a reaction chamber 502 and a precursordelivery system 504. The precursor delivery system 504 may be configuredfor supplying vapor phase precursor(s) to the reaction chamber 502employing the chemical delivery apparatus and sensors arrays of thecurrent disclosure to enable flow control of the precursors to thereaction chamber. It should be noted that the semiconductor processingapparatus 500 is a simplified schematic version of an exemplarysemiconductor processing apparatus and does not contain each and everyelement, i.e., such as each and every valve, gas line, heating element,and reactor component, etc. The semiconductor processing apparatus 500of FIG. 5 provides the key features of the apparatus to providesufficient disclosure to one of ordinary skill in the art. For example,the precursor delivery system 504 is illustrated with a single exemplarychemical delivery apparatus 200; however, it should be appreciated thatthe semiconductor process apparatus 500 and particular the precursordelivery system 504 may employ any number of chemical delivery apparatusto deliver any number of reactants to the reaction chamber 502associated with the semiconductor processing apparatus 500.

The exemplary semiconductor processing apparatus 500 may comprise areaction chamber 502 constructed and arranged to hold at least asubstrate 506. In some embodiments, the reaction chamber 502 may beconfigured for one or more of a deposition process, an etching process,or a cleaning process. For example, the reaction chamber 502 may beconfigured for atomic layer deposition (ALD) processes, or chemicalvapor deposition (CVD) processes. The substrate 506 may be disposed inthe reaction chamber 502 and held in position by a susceptor 508configured to retain at least one substrate thereon. The susceptor 508may comprise a heater 510 configured to heat the substrate to a suitableprocess temperature.

The precursor delivery system 504 may comprise a chemical deliveryapparatus such as the apparatus 200 (FIG. 2 ), the apparatus 300 (FIG. 3), or the apparatus 400 (FIG. 4 ). As a non-limiting example, theprecursor delivery system 504 is illustrated as utilizing the chemicaldelivery apparatus 200 of FIG. 2 . In abbreviated form, the chemicaldelivery apparatus 200 may comprise a vessel 202 configured forcontaining liquid chemical 206. The vessel 202 may include an inlet 208configured for providing one or more carrier gases into the inner volume204 of the vessel 202, wherein the inlet 208 comprises a valve 210 tocontrol the flow of carrier and may further comprise a flow controller512 (e.g., a mass flow controller) for controlling the mass flow of thecarrier gas into the vessel 202. The vessel 202 may also include anoutlet 212 configured for dispensing a vapor phase reactant to thereaction chamber 502. The outlet 212 may include a valve 214 forcontrolling the flow of the vapor phase reactant out of the vessel andmay further comprise a flow controller 514 (e.g., a mass flowcontroller) for controlling the mass flow of the vapor phase reactantout of the vessel 202. The vessel 202 may also include an array ofsensors 216 configured for detecting the fill level 210 of the liquidchemical 200 disposed in the inner volume 200 of the vessel 200. Thearray of sensors 216 may be vertically distributed within the innervolume 204 with an irregular vertical interval between adjacent sensorsand in particular embodiments the concentration of sensors may begreater in an upper portion of the inner volume 204 compared with theconcentration of sensors in a lower portion of the inner volume 204.

The precursor delivery system 504 may also include one or more heaters516 configured for heating the liquid chemical 206 in the vessel 202 toa desirable temperature set point. The one or more heaters 516 may bedisposed adjacent to the vessel 212 and may provide thermal energythrough the vessel 202 to the liquid chemical 206 disposed within theinner volume 204 of the vessel 202.

Although not shown in the exemplary precursor delivery system 504 ofFIG. 5 , the precursor delivery system 504 may include additionalchemical delivery apparatus of the current disclosure for dispensingmultiple vapor phase reactants to the reaction chamber 502. In addition,the precursor delivery system 504 may include a vessel configured forstoring and dispensing a purge gas to the reaction chamber 502.

One or more gas lines, such as exemplary gas line 518, may be in fluidcommunication with the precursor delivery system 504 to enable thesupply of vapor phase reactants and purge gas to the reaction chamber502. In particular embodiments, the precursor delivery system 504 may bein fluid communication with a gas dispenser 520 configured fordispensing vapor phase reactants and purge gas into the reaction chamber502 and over the substrate 506. As a non-limiting example, the gasdispenser 520 may comprise a showerhead as illustrated in block form inFIG. 5 . It should be noted that the although shown in block form, theshowerhead may be a relatively complex structure and may be configuredfor either mixing vapors from multiple sources, or maintaining aseparation between multiple vapors introduced into the showerhead.

The exemplary semiconductor processing apparatus 500 may also comprise agas removal system constructed and arranged to remove gases from thereaction chamber 502. For example, the removal system may comprise anexhaust port 522 disposed within a wall of the reaction chamber 502, anexhaust line 524 in fluid communication with the exhaust port 522, and avacuum pump 526 in fluid communication with the exhaust line 524 andconfigured for evacuating gases from within the reaction chamber 502.Once the gases have been exhausted from the reaction chamber 502utilizing the vacuum pump 526, the gases may be conveyed alongadditional exhaust line 528 and exit the apparatus 500.

The exemplary semiconductor processing apparatus 500 may furthercomprising a controller 530 operably connected to the precursor deliverysystem 504, the reaction chamber 502, and the removal system by means ofexemplary control lines 532A, 532B, and 532C. The controller 530 maycomprise electronic circuitry to selectively operate valves, heaters,flow controllers, manifolds, pumps and other equipment associated withthe semiconductor processing apparatus 500. Such circuitry andcomponents operate to introduce precursor gases and purge gases fromprecursor delivery system 504. The controller 530 may also control thetiming of precursor pulse sequences, temperature of the substrate andreaction chamber, and the pressure of the reaction chamber and variousother operations necessary to provide proper operation of thesemiconductor processing apparatus 500. The controller 530 may alsocomprise a memory 534 provided with a program to execute semiconductorprocesses when run on the controller 530. For example, the controller530 may include modules such as software or hardware components (e.g.,FPGA or ASIC) which perform certain semiconductor processes, such asetching processes, cleaning processes, and/or deposition processes, forexample. A module can be configured to reside on an addressable storagemedium of the controller 530 and may be configured to execute one orsemiconductor processes.

In some embodiments of the disclosure, the controller 530 may beconnected (either electrically and/or optically) to the array sensors216 and to other components associated with the semiconductor processingapparatus 500. For example, the array of sensors 216 may provide acontrol output to the controller 530 and the controller 530 may in turndeliver an associated control output to components associated with thesemiconductor processing apparatus 500 to enable a uniform reaction ratewithin the reaction chamber 502. As a non-limiting example, the reactionchamber 502 may be configured for a deposition process, such as, forexample, an atomic layer deposition process and/or a chemical vapordeposition process, and the array of sensors 216 may provide a controloutput to the controller 530 which in turn delivers an associatedcontrol output to the components associated with the semiconductorprocessing apparatus 500 to enable a uniform deposition rate of materialwithin the reaction chamber 502.

In some embodiments of the disclosure, the array of sensors 216 providea control output to the controller 530 dependent on the fill level 210of the liquid chemical 206 disposed within the vessel 202. For example,the control output from the array of sensors 216 may vary depending onthe fill level 210 of the liquid chemical 206 disposed within the innervolume 204 of the vessel 202. The fill level dependent control outputfrom the array of sensors 216 may be utilized by the controller 530 toadjust one or more control parameters that may affect the depositionrate of a material within the reaction chamber 500. As a non-limitingexample, the controller 530 may adjust one or more of the liquidchemical temperature, the substrate temperature, the flow rate of thecarrier gas, the flow rate of the vapor phase reactant, or the pulseperiod of the vapor phase reactant.

In a particular embodiment of the disclosure, the array of sensors 216may provide a fill level dependent control output to the controller 530and the controller 530 may in turn deliver an associated control outputto the one or more heaters 516 associated with the semiconductorprocessing apparatus 500. The associated control output from thecontroller 530 may be utilized to regulate the temperature of the liquidchemical 206 and enable a uniform deposition rate of material with thereaction chamber 502. As a non-limiting example, as the liquid chemicalis consumed and the fill level 210 decreases, the array of sensors 216may provide a fill level dependent control output to the controller 530indicating the fill level is decreasing. The controller 530 may deliveran associated control output to the one or more heaters 516 whichinstructs the one or more heaters 516 to increase the temperature of theliquid chemical 206 thereby increasing the vapor pressure of the liquidchemical 206 and counteracting any decrease in vapor phase reactant flowout from the vessel 202 to the reaction chamber 502. Therefore, in someembodiments, the array of sensors 216 may provide a fill level dependentcontrol output to the controller 530, and the controller 530 in turn mayprovide an associated control output to components associated with thesemiconductor processing apparatus 500 to deliver a uniform dose ofvapor phase precursor from the precursor delivery system 504 to thereaction chamber 502.

The embodiments of the disclosure may also include methods fordispensing a vapor phase reactant to a reaction chamber. In someembodiments the method may comprise: flowing a carrier gas into an inletof a vessel having an inner volume configured to contain a liquidchemical; sensing a fill level of the liquid chemical by providing anarray of sensors configured for detecting a fill level of the liquidchemical disposed within the inner volume; wherein the array of sensorare vertically distributed with the inner volume with an irregularvertical interval between adjacent sensors; and flowing a vapor phasereactant from an outlet of the vessel to a reaction chamber.

In some embodiments, the array of sensors may comprise a linear array ofsensors. In some embodiments, the vertical interval between adjacentsensors may increase form an upper-most sensor to a lower-most sensorsand in particular embodiments, the concentration of sensors may begreater in an upper portion of the inner volume compared with theconcentration of sensors in a lower portion of the inner volume. In someembodiments, the array of sensors may comprise an array of digitalsensors that either detects the presence or absence of a liquid at thesensor location and in particular embodiments the digital sensors maycomprise digital ultrasonic detectors.

In some embodiments, the method of sensing a fill level of the liquidchemical may further comprise providing an additional array of sensorsconfigured for detecting the fill level of the liquid chemical, whereinthe additional array of sensors are vertically distributed within theinner volume with an irregular interval between adjacent sensors. Insome embodiments, the additional array of sensors may comprise a lineararray of sensors and the vertical interval between the adjacent sensorsmay increase from an upper-most sensor to a lower-most sensors. In someembodiments, the additional array of sensors may comprise an array ofdigital sensors that either detects the presence or absence of a liquidat the sensor location and in particular embodiments the addition arrayof sensors may comprise an array of digital ultrasonic sensors. In someembodiments, the methods of sensing the fill level of a liquid chemicaldisposed within the inner volume may comprise providing an array ofsensors and an additional array of sensors, wherein each sensor of thearray and the additional array may be disposed at a different verticalposition within the inner volume of the vessel.

The methods of the disclosure may also comprise creating a controloutput from the array of sensors and providing the control output to acontroller associated with a semiconductor deposition apparatus. Themethods of the disclosure may further comprise creating an associatedcontrol output from the controller which may be delivered to thesemiconductor deposition apparatus to enable a uniform deposition rateof a material. In some embodiments, the associated control output fromthe controller is delivered to one or more heaters associated with thesemiconductor deposition apparatus and configured for heating the liquidchemical to thereby regulate the temperature of the liquid chemical andenable the uniform deposition rate of the material.

The example embodiments of the disclosure described above do not limitthe scope of the invention, since these embodiments are merely examplesof the embodiments of the invention, which is defined by the appendedclaims and their legal equivalents. Any equivalent embodiments areintended to be within the scope of this invention. Indeed, variousmodifications of the disclosure, in addition to those shown anddescribed herein, such as alternative useful combination of the elementsdescribed, may become apparent to those skilled in the art from thedescription. Such modifications and embodiments are also intended tofall within the scope of the appended claims.

What is claimed is:
 1. A sensor array configured for detecting the filllevel of a liquid in a vessel, the apparatus comprising: a verticalsupport; and an array of sensors configured for detecting a fill levelof the liquid disposed within an inner volume of the vessel, wherein thearray of sensors comprises a plurality of sensors which are verticallydistributed along the vertical support with an irregular verticalinterval between adjacent sensors;
 2. The sensor array of claim 1,wherein the array of sensors comprises a linear array of sensors.
 3. Thesensor array of claim 1, wherein the vertical interval between adjacentsensors increases from an upper-most sensor to a lower-most sensor. 4.The sensor array of claim 1, wherein an individual sensor is a digitalsensor that detects either the presence of the liquid or the absence ofthe liquid.
 5. The sensor array of claim 4, wherein the array of sensorcomprises an array of digital ultrasonic sensors.
 6. A precursordelivery system comprising the sensor array of claim
 1. 7. Asemiconductor processing apparatus comprising the precursor deliverysystem of claim 6.